Add a sanity check to make sure the correct versions of Net::SSH and Net::SFTP are installed

git-svn-id: http://svn.rubyonrails.org/rails/tools/switchtower@3373 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Add a sanity check to make sure the correct versions of Net::SSH and Net::SFTP are installed.
+
 * Added a cleanup task to remove unused releases from the deployment directory
 
 * Allow password to be reentered on sudo if it was entered incorrectly

lib/switchtower/configuration.rb

@@ -3,7 +3,6 @@ require 'switchtower/logger'
 require 'switchtower/scm/subversion'
 
 module SwitchTower
-
   # Represents a specific SwitchTower configuration. A Configuration instance
   # may be used to load multiple recipe files, define and describe tasks,
   # define roles, create an actor, and set configuration variables.

lib/switchtower/ssh.rb

@@ -1,6 +1,16 @@
 require 'net/ssh'
 
 module SwitchTower
+  unless ENV['SKIP_VERSION_CHECK']
+    require 'switchtower/version'
+    require 'net/ssh/version'
+    ssh_version = [Net::SSH::Version::MAJOR, Net::SSH::Version::MINOR, Net::SSH::Version::TINY]
+    required_version = [1,0,5]
+    if !Version.check(required_version, ssh_version)
+      raise "You have Net::SSH #{ssh_version.join(".")}, but you need at least #{required_version.join(".")}"
+    end
+  end
+
   # A helper class for dealing with SSH connections.
   class SSH
     # An abstraction to make it possible to connect to the server via public key

lib/switchtower/transfer.rb

@@ -1,6 +1,15 @@
 begin
+  require 'switchtower/version'
   require 'net/sftp'
-  SwitchTower::SFTP = true
+  require 'net/sftp/version'
+  sftp_version = [Net::SFTP::Version::MAJOR, Net::SFTP::Version::MINOR, Net::SFTP::Version::TINY]
+  required_version = [1,1,0]
+  if !version_check(required_version, sftp_version)
+    warn "You have Net::SFTP #{sftp_version.join(".")}, but you need at least #{required_version.join(".")}. Net::SFTP will not be used."
+    SwitchTower::SFTP = false
+  else
+    SwitchTower::SFTP = true
+  end
 rescue LoadError
   SwitchTower::SFTP = false
 end

lib/switchtower/version.rb

@@ -1,9 +1,30 @@
 module SwitchTower
   module Version #:nodoc:
+    # A method for comparing versions of required modules. It expects two
+    # arrays as parameters, and returns true if the first is no more than the
+    # second.
+    def self.check(expected, actual) #:nodoc:
+      good = false
+      if actual[0] > expected[0]
+        good = true
+      elsif actual[0] == expected[0]
+        if actual[1] > expected[1]
+          good = true
+        elsif actual[1] == expected[1] && actual[2] >= expected[2]
+          good = true
+        end
+      end
+    
+      good
+    end
+
     MAJOR = 0
     MINOR = 10
     TINY  = 0
 
     STRING = [MAJOR, MINOR, TINY].join(".")
+    
+    SSH_REQUIRED = [1,0,5]
+    SFTP_REQUIRED = [1,1,0]
   end
 end

switchtower.gemspec

@@ -19,8 +19,8 @@ Gem::Specification.new do |s|
   s.bindir = "bin"
   s.executables << "switchtower"
 
-  s.add_dependency 'net-ssh', '>= 1.0.5'
-  s.add_dependency 'net-sftp', '>= 1.1.0'
+  s.add_dependency 'net-ssh', ">= #{SwitchTower::Version::SSH_REQUIRED.join(".")}"
+  s.add_dependency 'net-sftp', ">= #{SwitchTower::Version::SFTP_REQUIRED.join(".")}"
 
   s.author = "Jamis Buck"
   s.email = "jamis@37signals.com"